Embodiments of the inventive concepts relate to pixels of an image sensor, image sensors including the pixels, and an image processing system including the image sensors, and more particularly, to pixels including transistors which provide improved performance, image sensors including the pixels, and image processing systems including the image sensors.
Image sensors are devices that convert an optical image into an electrical signal. Image sensors are used in digital cameras or other types of image processing devices. Image sensors may include a plurality of pixels.
Mechanical shutter mode and electronic shutter mode are largely used to control an exposure time that determines amount of photocharges corresponding electrical signal. In mechanical shutter mode, a mechanical device blocks light to pixels. Electronic shutter mode is usually used in complementary metal-oxide semiconductor (CMOS) image sensors. In electronic shutter mode, an integration time during which photocharges are generated and accumulated is electrically controlled. Electronic shutter mode includes rolling shutter mode and global shutter mode.
In rolling shutter mode, an integration time is controlled separately for each row in a pixel array. In global shutter mode, an integration time is controlled uniformly throughout all rows in a pixel array.
Global shutter mode has an advantage of eliminating image distortion caused by different integration times among rows. However, it also has some disadvantages in terms of the degree of integration or signal transmission, and therefore, some improvements are desired.